Fabric for testing amylase activity

ABSTRACT

A TEST FABRIC FOR THE DETERMINATION OF AMYLASE ACTIVITY COMPRISING A FABRIC IMPREGNATED WITH A MIXTURE OF A FINELY DIVIDED COLORED PIGMENT SUCH AS CARBON BLACK AND A GELATINIZED STARCH BINDER.

United States Patent 3,595,754 FABRIC FOR TESTING AMYLASE ACTIVITY Theodore Cayle, Morganville, and Joseph W. Creely, Middlesex, N.J., assignors to Baxter Laboratories, Inc., Morton Grove, Ill. No Drawing. Filed Feb. 12, 1969, Ser. No. 798,799 Int. Cl. (109k 3/00 US. Cl. 195-99 Claims ABSTRACT OF THE DISCLOSURE A test fabric for the determination of amylase activity comprising a fabric impregnated with a mixture of a finely divided colored pigment such as carbon black and a gelatinized starch binder.

BACKGROUND OF THE INVENTION In the average household, the stains and other discolorations which must be removed from clothing and household linens are largely made of proteins and carbohydrates. Both of these materials can form a hard, insoluble, matrix about and within the individual fibers of a fabric to form a stain which often cannot be removed by conventional washing.

In response to this, the soap and detergent industry has developed new lines of products for removing or discoloring such stains. One of the newest discoveries in this area lies in the use of enzymes for breaking down protein and carbohydrate matrices within fabrics, which permits the stain to be removed by the action of soap or detergent.

Typically, the enzymes used for this purpose are divided into two groups: the protease enzymes, which break down protein molecules; and the amylase enzymes, which break down carbohydrates. Frequently, enzymes selected from both groups are used in formulations for removing stain, since any given stain may contain a protein, a carbohydrate, or a mixture of the two.

It is desirable in the testing of the effect of a given enzyme formulation against stains to be able to separate the effectiveness of the formulation against proteins from the effectiveness of the formulation against carbohydrates. Up to the present time, there has been no convenient and accurate test for specifically determining the effect that an enzyme formulation has against a carbohydrate alone, separate and apart from the effect of the same formulation against protein. Certain test fabrics have been used in the past which show the stain-removing capability of enzyme formulations which are effective against proteins, but these fabrics cannot be used to quantitatively measure the effectiveness of a formulation against carbohydrates found in stains.

SUMMARY OF THE INVENTION This invention relates to a test fabric for specifically determining the effectiveness of enzyme formulations against carbohydrates. This is important as a research tool because, although a given enzyme formulation may be effective against many stains by breaking down the protein constituents thereof, it may be ineffective against other stains in which the carbohydrate content is significant. Heretofore it has been difiicult to precisely determine the mechanism of stain removal by a given formulation, ie whether the proteins or the carbohydrates have been broken down in the removal process. By this invention, the precise amylase activity of a formulation can be determined separate and apart from its activity against proteins.

In accordance with this invention, a test fabric is provided which is impregnated with a mixture of a finely di- 95,754 Patented July 27, 1971 vided colored pigment and sufficient gelatinized starch to bind the pigment to the fabric.

Typically, the finely divided colored pigment is a form of carbon black such as lampblack, but other known or ganic and inorganic pigments can be used, such as paint pigments, manganese dioxide, iron oxide, crushed slate, pumice, and other colored rock or mineral, powdered aluminum, zinc dust, and powdered organic resins such as polystyrene, preferably containing a coloring material.

The purpose of the pigment is to act as a color indicator on the test fabric, being maintained thereon by the gelatinized starch binder.

The test fabric can be washed without a major loss of pigmentation. However, when the fabric is placed in contact with a formulation having a significant amylase activity, the starch binder is degraded, and pigment can be washed out of the fabric, causing a lightening in the fabric color. Thus the test fabric of this invention can be used in colorimetric testing for determining the amylase activity of stain-removing formulations, as well as in other formulations in which the amylase activity is to be measured. The degree of the amylase activity present in a given formulation can be determined colorimetrically by observation of the degree of pigment loss from the fabric after subjecting it to action by the formulation and washing the fabric. Nevertheless, the fabric of this invention is essentially nonresponsive to formuations having only protease activity and no amylase activity.

The gelatinized starch used herein is typically prepared by heating dry starch in water to burst starch granules and to hydrate the starch to form a gummy mass, which is then mixed with the pigment and applied to the fabric to bind the pigment on the fabric. Typically, from one to three parts by weight of gelatinized starch are present on the fabric per one part by weight of pigment.

The fabric used herein is preferably made of cellulosic fibers, e.g. cotton, rayon, or linen. If desired, however, fabrics of other well known fibers such as polyester, nylon and wool can be used if desired. Typically, the dry fabric product of this invention is impregnated with from about three to ten weight percent, based. on the weight of the fabric, of a mixture of pigment and gelatinized starch.

The following example is given for illustrative purposes only. It is clear that this invention can be practiced in many different embodiments in accordance with the general principles set forth herein.

Example One part by weight (25 grams) of lampblack was placed in 100 grams of methanol, which. is a dispersing agent for lampblack. This mixture was then diluted with 500 ml. of water. A second mixture was prepared by adding two parts by weight (50 grams) of Staley brand acorn starch to 950 ml. of distilled water. This second mixture was heated slowly to C. with rapid mixing, and then allowed to cool to 40 C. by standing at room temperature. During this heating step, the starch was converted into a gelatinized material. After the cooling of the second mixture to 40 C. the former mixture containing the lampblack was added, and the combined mixture was stirred for 30 minutes.

About 10 yards of bleached linen cloth, having a width of 6 inches, was immersed in the mixture prepared above. The cloth was then squeezed between rubber rollers, reimmersed in the mixture, and squeezed once again between rubber rollers to provide a cloth uniformly penetrated by the aqueous lampblack-starch mixture.

The cloth was then dried in an oven for 30 minutes at 88 C., and then allowed to age for 24 hours at room temperature.

Uniformly sized strips of the cloth prepared above were Washed for 15 minutes at 50 C. in commercial test washing equipment (Launder-Ometer, made by Atlas Electric Devices Company of Chicago, Ill.) in the presence of a detergent of the following formulation:

Weight percent An alkyl-benzene-sulfonate 10 Sodium tripolyphosphate 40 Sodium borate 10 Sodium sulfate 30 Sodium metasilicate Carboxymethylcellulose 1 Optical brighteners, dyes, perfumes, etc. Balance In each washing run, 200 cc. of a 0.5 weight percent water solution of the above detergent was placed along with the cloth in the one pint Washing chamber of the laundering equipment. In some of the runs, 0.85 weight percent, based upon the weight of the detergent added, of a commercially available protease enzyme, operative under alkaline conditions, was also added, while in other runs one weight percent, based upon the weight of the detergent, of a commercially available detergent amylase enzyme was added. In yet other runs, both enzymes were added to the detergent in the above proportions.

The washed fabric samples were rinsed and dried, and the reflectance of the sample was measured in a Gardner reflectometer, using alternatively green and blue filters.

Average results of five samples of the fabric of this invention for each experimental run were measured, the results being shown below as a percentage reflectance. In all cases both sides of each fabric were measured, the figures below being the average percentage reflectance of both sides of every fabric sample:

tivity which consists essentially of a fabric impregnated with a mixture of a finely divided colored pigment and suflicient gelatinized starch to bind said pigment to the fabric.

5 2. The test fabric of claim 1 impregnated with from about 3 to weight percent of said mixture, based on the weight of the fabric.

3. The test fabric of claim 1 in which from 1 to 3 parts by weight of gelatinized starch are present per one 10 part by weight of pigment.

4. The test fabric of claim 1 in which said fabric comprises cellulosic fibers.

5. The test fabric of claim 1 in which said pigment is finely powdered carbon.

6. The test fabric of claim 1 in which said fabric comprises cellulosic fibers and is impregnated with from 3 to 10 weight percent, based on the weight of the fabric, of a mixture of 1 part by weight of finely powdered carbon and 2 parts by weight of gelatinized starch.

7. The process of preparing a test fabric for the deterpersion of gelatinized starch with said dispersion and mixing intimately, and thereafter applying the resulting mixture to fabric, and drying said fabric whereby the pigment is bound to the fabric by the starch.

8. The process of claim 7 in which said alcohol is methanol.

9. The process of claim 8 in which said fabric comprises cellulosic fibers.

It can be seen from the above data that the reflectance of the cloth is sharply higher after being washed with an amylase enzyme, indicating that a large amount of the lampblack pigment had been removed from the cloth. It can also be seen that only a small amount of the lampblack pigment is removed from the cloth when washed with a detergent alone or with a detergent in the presence of a protease enzyme which is active at alkaline pH.

Thus the test cloth of this invention provides a method of easily and economically detecting the presence of amylase enzyme without any interference from any protease enzyme which may also be present.

If desired, the finely divided carbon can be dispersed in other alcohols having up to three carbon atoms such as ethanol or isopropanol.

What is claimed is:

1. A test fabric for the determination of amylase ac- 10. The process of claim 7 in which said resulting mix- 5 ture is applied to the fabric to impregnate said fabric with from 3 to 10 weight percent of carbon and starch measured after drying, based on the weight of the fabric.

References Cited UNITED STATES PATENTS 2,413,320 12/1946 Grifiin et al 862X 3,089,828 5/1963 Tsuk 195-103.5(R)

A. LOUIS MONACELL, Primary Examiner I. R. HOFFMAN, Assistant Examiner U.S. Cl. X.R. -l03.5R 

